Process and apparatus for the recovery of the constituents of photographic film material



R. SPELLING 2,013,769 PROCESS AND APPARATUS FOR THE RECOVERY OF THE Sept. l0, 1935.

Patented Sept. 10, 1935 'I' FFICE APPARATUS FOR THE RECOVERY 0F THE CONSTITUENTS 0F PHOTOGRAPHIC FILM MATERIAL PROCESS AND Richard Spelling, Berlin-Grunau, Germany Application May 21, 1932, Serial No. 612,788 In Germany May 22, 1931 3 Claims.

Thepresent invention relates to process and apparatus for the recovery of the constituents oi photographic film material.

In accordance with the invention the photographic iilm, the constituents of which are to be recovered, is iirst passed through one or more chambers charged with a solvent for the cellulose ester of the film, whereby the cellulose ester is dissolved, with the result that ultimately, only a thin lm still remains, consisting of the true photographic layer and the so-called prepared layer which generally consists of albumen and serves to promote adhesion between the true photographic layer and the cellulose ester support. These latter two layers are then dissolved in one or more chambers filled with a solvent for the photographic and the prepared layer, for example, warm water.

Now, since during the dissolution of the cellulose ester layer, the strength of the film diminishes progressively and ultimately there remain only the photographic layer and the prepared layer, the mechanical strength of the film decreases to such an extent that special means become necessary to prevent tearing of the thus weakened film. In accordance with the present invention this tearing of the lm is avoided by placing the lm between two bands of wire gauze, which are conducted parallelly in a zigzag path through the solvent for the cellulose ester and one or more chambers filled with a solvent for the photographic and prepared layer, for example, warm water. In this manner the nlm is protected to a large extent from mechanical strain and in particular from tearing strain, with the result that the cellulose ester can be removed practically completely from the albumen layer without mechanical destruction of the latter taking place.

The machine, the subject of the present invention, is illustrated diagrammatically in the accompanying drawing.

Figure 1 shows a diagrammatic longitudinal section,

Figure 2 a transverse section through the machine at the position indicated in Figure l by line 2 2, and

Fig. 3 shows positions of the two wire gauze bands with the photographic lm held between them.

In Figure 1, I is a container divided `into three chambers, A, B and C, by means of transverse walls 2 and 3. Chambers A and B are charged with a solvent for the cellulose esters, present in the film material to be treated. Chamber C is 5 lled with water, which is heated by means of the hot coils 2|.

Two endless revolving bands 6 and l, consisting of wire gauze, are passed through these chambers by means of the rollers, 4, 5 and 5a.. The rollers 10 5 are so adjustable that their distance from the rollers I and consequently the length of travel of the revolving bands in the chambers can be altered. The revolving bands 6 and 'I pass externally back to the machine over the rollers 8, 15 9, I0 and II and I2, I3 and I4, respectively, and the tension of the bands can be regulated by means of the tensioning rollers 22 and 23 by an appropriate adjustment of the weights 25 and 24.

The lm material is placed between the revolv- 20 ing bands by means of the rollers II and I4 and indeed longer lengths, such as for example, played out cine iilms, can with advantage be led to the rollers I I and I4 from the reel 26, placed in front, in such a manner that the nlm is automatically 25 unwound and fed into the revolving bands without special attention.

The lm is now led between the revolving bands over the rollers 4, 5 and 5c through the chambers A and B, filled with a solvent for the cellulose es- 30 ters, with the result that the cellulose esters are dissolved. The solution of the esters can be eX- pedited by agitation of the solution, for example, by the use of the stirrers I6 and I1. Moreover, the ends 2l and 28 of the stirrers can be con- 35 structed in the form of brushes, which mechanically promote the solution of the cellulose ester layer by brushing and keeping the mesh of the revolving bands free from concentrated cellulose ester solution or swollen cellulose ester.

At the point where the revolving bands leave the chamber B which is lled with a solvent for the cellulose ester a mechanical device is introduced with advantage, :for example, a brush 20, which removes the solvent adhering to the re- 45 volving bands and to the lm residue between the bands and prevents the carrying over of considerable quantities of the solvent into the chamber C which is lled with warm water.

In chamber C the photographic layer and the 50 prepared layer are now dissolved by means of warm water. This process of dissolution can be facilitated by mechanical treatment of the lm lying between the revolving bands by means of brushes I8 and I8. The revolving bands 6 and I which are by this time free from the last residues of lm then leave the water chamber C and return to the rollers II and I4 after passing over the rollers 9 and I0 and I2 and I3, respectively, and there take up new lm material.

It should still be observed, as may be seen from the illustration, that chambers A and B should with advantage be closed as completely as possible to prevent considerable loss of the solvent by evaporation. The motive power of the machine can be provided through the pulley belt 29 by the use of a suitable power machine (not shown). This pulley belt works the stirrers I6 and I'I by means of the shaft 3D and the crank mechanism 3I and 32. From the shaft 3G, for example by means of two chain sprockets 33 and 34 and a chain 35 the shaft 36 can be driven in a suitable manner and from the shaft 36 the rollers 5a, 8 and II are driven, for example by means of a bevel wheel 31.

I claim:

1. Method for the recovery of the constituents of photographic lm which comprises supporting -the photographic lm between travelling endless bands of wire gauze and passing the film while it is so supported successively through a plurality of bodies of solvents for said constituents. 2. Process as defined in claim 1 in which the ilm is passed successively through a bath of a solvent for cellulose ester and a bath of water. 3. A device for the recovery of the constituents of photographic lm material which comprises a container which is divided by means of transverse walls into three chambers for solvents for said constituents, rollers associated with said chambers, two endless revolvable bands of wire gauze arranged to pass over said rollers through the said container in parallel relationship to each other and to carry the said photographic lm material between them down into, through and up out of the three chambers successively, and 20 a mechanically actuated stirrer in at least one of said chambers the lower end of which is constructed in the form of a brush, said brush being located so as to contact with one of said wire gauze bands.

RICHARD SPELLING. 

